This work aimed at preparing supertough PA6 blends with only a small :amount of elastomer. The PA6/SEBS-g-MA/PP blends were obtained by melt extrusion, in which the core-shell particles (PP as: core and SEBS-g-MA as shell) could be formed in situ in PA6 matrix. The morphology PA6 blends was, explained by both the thermodynamic factor (interfacial tension and spreading coefficient) and the kinetic factor (viscosity ratio). By adjusting the loading of PP and SEBS-g-MA, the core-shell particles with suitable size could be obtained, and the notched impact strength of the PA6 blends could be significantly improved. The effects of the loading of PP and SEBS-g-MA on tensile properties were also studied. Consequently, PA6 blends with high tensile strength and excellent impact strength could be obtained by loading only a small amount of SEBS-g-MA.